gplugin/gplugin

When we renamed all the python files to say python3 we missed the actual directory

Testing Done:
Compiled locally, built debian and fedora packages without issues.

Reviewed at https://reviews.imfreedom.org/r/106/
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REPOSITORY = "gplugin/gplugin"
REPOSITORY_TYPE = "mercurial"
LAND_DEST_BRANCH = "develop"
LAND_PUSH = False